title: Evaluation of preservative effectiveness of liquid crystalline systems with retynil palmitate by the challenge test and D-value.
abstract: The objective of this work was to evaluate the preservative effectiveness of liquid crystalline systems containing retynil palmitate (RP) by the challenge test (CT) and D-value. A system was developed containing water, silicon glycol copolymer, and polyether functional siloxane with 1% RP added. The analyses were carried out by methods in the U.S. Pharmacopeia (USP 31, 2008) using the microorganisms Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger. The CT showed that after 7 days, all microorganisms were eliminated except A. niger, which maintained viability for at least 28 days after inoculation. Moreover, the microorganisms E. coli, P. aeruginosa, S. aureus, C. albicans, and A. niger presented different growth behaviors, evidenced by differences among the D-values calculated. It was concluded that the CT and D-value were efficient methods for evaluation of the preservative property of these formulations.
authors.affiliation: UNESP, Programa de Pós-graduação em Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas, Rodovia Araraquara-Jaú, km 1, CEP 14801-902, Araraquara-SP, Brazil.
authors.forename: Marlus
authors.initials: M
authors.lastname: Chorilli
authors.forename: Gislaine Ricci
authors.initials: GR
authors.lastname: Leonardi
authors.forename: Hérida Regina Nunes
authors.initials: HR
authors.lastname: Salgado
authors.forename: Maria Virgínia
authors.initials: MV
authors.lastname: Scarpa
mesh_terms: D001234:Aspergillus niger / Q000254:growth & development; D002176:Candida albicans / Q000254:growth & development; D015169:Colony Count, Microbial; D003358:Cosmetics / Q000737:chemistry*; D004224:Diterpenes; D004340:Drug Contamination / Q000517:prevention & control; D004926:Escherichia coli / Q000254:growth & development; D050866:Liquid Crystals; D011310:Preservatives, Pharmaceutical; D011550:Pseudomonas aeruginosa / Q000254:growth & development; D000084562:Retinyl Esters; D013211:Staphylococcus aureus / Q000254:growth & development; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D003358:Cosmetics; D004224:Diterpenes; D011310:Preservatives, Pharmaceutical; D000084562:Retinyl Esters; D014801:Vitamin A; C014794:retinol palmitate